Laws on this vary by jurisdiction. We cannot answer this accurately without knowing your location.
As many as you want, provided you're legally able to own them.
The "better" question would be "how many murders, rapes, and robberies are prevented by home guns ?"
In many instances, yes.
No. Machine guns will beat Gatling guns.
read the Second amendment. When the Constitution uses the phrase "the people" it means the individuals who are citizens.
You have to earn the golden guns
Elvis Presley was known to be a gun enthusiast and owned a significant collection of firearms. It is estimated that he had around 30 guns, including handguns, rifles, and shotguns. His passion for firearms was reflected in his personal life and his home, Graceland, where many of these guns were displayed.
Your question assumes that people shouldn't be able to buy guns "in the market", whatever that means, which is far from proven.
About 1/3rd of American households own at least one firearm
to scare people
because of protection in your home for your kids especially
guns are fired in less than 2% of home-intruders